Roth 403(b) vs Roth 401(k): What Is the Actual Difference?
Structurally identical. Same tax treatment, same limits, same rules. The real difference is the same investment fee gap as the traditional versions. Updated 26 October 2026.
The short answer
Roth 403(b) and Roth 401(k) are structurally identical. Same $24,500 contribution limit, same after-tax contribution treatment, same tax-free growth and withdrawal rules, same 5-year clock requirement, same RMD exemption (since 2024). The Roth designation does not change the underlying plan type or its investment options and fees.
Where they differ
Exactly the same places as the traditional versions differ. A Roth 403(b) in an annuity plan still has 1.5-3% annual fees. A Roth 401(k) with index funds still has 0.03-0.1% fees. The Roth wrapper changes the tax treatment of contributions and withdrawals; it does not change the investment products available or their costs.
Match implications
Even if you elect 100% Roth contributions, your employer match almost always goes into the traditional (pre-tax) bucket. Under SECURE 2.0, employers may optionally offer Roth matching contributions (after-tax employer match), but as of 2026 most have not implemented this. Result: if you are a "full Roth" contributor, you will still have a pre-tax component in your account from employer matching.
The 5-year clock
Each Roth 403(b) and Roth 401(k) has its own 5-year clock starting with the first Roth contribution to that plan. Qualified distributions (tax-free) require: (1) the 5-year clock has run, and (2) you are over 59.5, disabled, or deceased. Rolling a Roth 403(b) to a Roth IRA resets the 5-year clock to the earlier of the IRA or the plan, which can be beneficial if the IRA has been open for five years already.
When to use Roth 403(b) or Roth 401(k)
- You expect to be in a higher tax bracket in retirement than now (early career, high-growth earners)
- You are in a low marginal tax bracket today (taxable income under $47,150 single or $94,300 married filing jointly in 2026)
- You plan to retire in a state with income tax but may move to a no-income-tax state (check noincometaxstates.com for which states apply)
- You want to avoid RMDs on this account (Roth employer plan accounts are now exempt from RMDs during your lifetime, like Roth IRAs)
- You have a long time horizon and tax-free compounding benefit is substantial
Worked example: Traditional vs Roth (same tax bracket)
Assumptions: $10,000 contributed, 22% tax bracket now and in retirement, 7% return, 30 years, 0.1% fees.
Traditional
Saves $2,200 tax today
$10,000 grows to ~$74,000
Withdraw: taxed at 22%
After-tax: ~$57,700
Roth
Costs $2,200 more take-home today
$10,000 grows to ~$74,000
Withdraw: tax-free
After-tax: ~$74,000
At the same tax rate the two are a wash per dollar of take-home pay. Invest the traditional saver's $2,200 tax saving in the same funds at the same 6.9% net return and it grows to about $16,300, which brings the traditional total to about $74,000, level with Roth. In practice that $2,200 usually sits in a taxable account and loses a little to tax along the way. At the same bracket, Roth pulls ahead mainly if you contribute the full $24,500 limit, because a Roth dollar under the cap shelters more than a pre-tax one. If you expect a lower bracket in retirement, traditional wins; a higher one, Roth wins.